Natural photosynthesis

This involves mainly spectroscopic studies of the primary light capture and electron transfer processes in Photosystem II (PS II). This protein complex, found in plants and photosynthetic bacteria, generates molecular oxygen by photo-catalytic oxidation of water and supports most animal life on earth. The water splitting reaction occurs within a unique, Mn4- Ca active site of PS II, whose detailed molecular structure and mechanism present great challenges for chemical understanding. The centre executes the most energetically demanding reaction in nature by means not yet properly understood.

Our group has developed ultra-high purity preparations of photosystem II material from plants, which are a unique experimental resource. We employ a broad range of spectroscopic tools to study catalytic processes in PS II. These include: Fourier transform infrared spectroscopy (FTIR), CW and pulsed EPR and magneto-optical spectroscopy.

An active theoretical program operates within the group. This involves simulation studies of the spectral signatures of paramagnetic intermediates within the water oxidising catalytic cycle, to explore the mechanism, and high level quantum computational studies of Mn cluster geometries and oxidation states.